this is a question only a Vet can give an answer too......IMO and I AM NOT A VET so this is my opinion only...that he'll be okay.
please read all the following on allergies....itching ears(if there are NO mites) are caused by allergies...and allergies are caused mainly by grains in the food, change to a GRAIN FREE CANNED food. NO dry food and these symptoms would most likely go away..
http://www.medhelp.org/posts/Cats/CAT-Allergies/show/1967931
ps.I DO NOT agree with the so called natural remedies mentioned, these can be ingested when a cat licks themselves and many products like these are dangerous...